Senior Software Engineer

Sr. Software Engineer – Mobility Engineering

Who We Are
WEX Inc. is a leading financial technology service provider across a wide spectrum of sectors, including fleet mobility, benefits, and corporate payments. At WEX, we’re on a mission to simplify the business of running a business.

What You’ll Do
We are seeking a Senior Software Engineer to join our North America Mobility Engineering team. The role will be located in Seattle, WA. This team builds fleet management and mobility payments solutions for enterprise customers and partners across North America. Our global Mobility Engineering organization spans the U.S., Brazil, and India and powers SaaS and API platforms supporting critical fleet credit issuance and transaction processing at scale.

As a Sr. Software Engineer, you will:

• Design, develop, and maintain robust, scalable, and high-performance backend systems using Java and/or C#.
  

• Build and maintain public REST APIs and internal gRPC APIs to support inter-service and inter-system communication.
  

• Lead system design efforts and collaborate with other senior engineers to drive alignment and architectural consistency.
  

• Write automated tests including unit, integration, end-to-end, concurrency, and performance tests.
  

• Identify bottlenecks in existing systems and implement improvements for scalability, stability, and maintainability.
  

• Drive automation across testing, monitoring, healing, and deployment pipelines to reduce time-to-market.
  

• Collaborate closely with cross-functional partners including product managers, designers, and fellow engineers.
  

• Conduct thorough code reviews and mentor junior and mid-level engineers on engineering best practices.
  

• Troubleshoot complex production issues, perform root cause analyses, and develop long-term resolutions.
  

• Evaluate and compare emerging technologies to guide technical decisions.
  

• Create and maintain robust documentation including design docs, runbooks, change logs, and readiness plans.
  

• Support production systems through proactive monitoring and incident response to ensure reliability and availability.
  

• Act as a technical lead or single-threaded owner (STO) on cross-team projects, unblocking others and delivering impact.

What You’ll Bring

• Bachelor’s degree in Computer Science, Software Engineering, or related field.
  

• 8–10 years of professional software engineering experience.
  

• Deep knowledge of data structures, algorithms, object-oriented programming, and system design principles.
  

• Proven experience designing and developing internet-scale backend services with high availability and performance.
  

• Strong proficiency in Java or C#, Spring Boot framework, RESTful API design, SQL, and ODATA framework.
  

• Excellent communication skills and a collaborative, growth-oriented mindset.
  

The base pay range represents the anticipated low and high end of the pay range for this position. Actual pay rates will vary and will be based on various factors, such as your qualifications, skills, competencies, and proficiency for the role. Base pay is one component of WEX's total compensation package. Most sales positions are eligible for commission under the terms of an applicable plan. Non-sales roles are typically eligible for a quarterly or annual bonus based on their role and applicable plan. WEX's comprehensive and market competitive benefits are designed to support your personal and professional well-being. Benefits include health, dental and vision insurances, retirement savings plan, paid time off, health savings